The analyses are among more than 700 pages of documents that were posted on the Food and Drug Administration's website in advance of a meeting of scientific advisers the agency has scheduled for next week to once again consider whether to allow the drug — Avandia — to remain on the market.

During a briefing for reporters Thursday, FDA officials cautioned that agency experts remained split about the drug.

"There's not complete unanimity within the FDA about interpretation of these data, and that's one of the reasons we're going to the advisory committee," said Janet Woodcock, director of the FDA's center for drug evaluation and research.

Steven Nissen, a Cleveland Clinic cardiologist who first raised questions about Avandia's safety and has campaigned to have it removed from the market, was unmoved: "What they were able to do in many ways was confirm my worst fears about the drug. … This drug is unsafe."

GlaxoSmithKline, which makes Avandia, argued that many other studies have found it to be both safe and effective.

Last month, two other teams of researchers — one of which conducted an analysis of more than 227,500 Medicare patients, the largest such study to date — reported that Avandia increases the risk of heart problems and stroke.